Rolling-mill roll of barrel-width adjustable type

ABSTRACT

The present invention provides a rolling-mill roll of a barrel-width adjustable type improved in strength by preventing stress concentration in a torque transmission structure for transmitting the torque from drive side roll to another roll. The connecting rod coaxially projected from the drive side arbor is inserted into the sleeve, and the rolls are mounted onto the circumferences of the connecting rod and the sleeve. The connecting rod and the sleeve are supported in a housing via bearings and are coupled with each other by a screw shaft mechanism so that the sleeve is axially movable to vary the barrel width. The complementary engagement between the spline or key for transmitting the torque of the arbor to the sleeve is made at a position offset outward from the axial center of the sleeve bearing so that the complementary engagement is not affected by the bending of the roll due to the rolling reaction and thus a stress concentration is prevented.

TECHNICAL FIELD

The present invention relates to a horizontal roll for rolling shapesteels of various sizes, particularly to a rolling-mill roll of whichthe barrel width is freely adjustable in accordance with a change in thewidth of the shape steel to be rolled.

BACKGROUND ART

In rolling shape steels having various sizes, a barrel width of ahorizontal roll in a universal mill, edging mill or the like must bechanged in accordance with the sizes of the shape steel to be rolled. Inthe prior art, many sets of rolls having different barrel widthscorresponding to the sizes of the shape steels to be rolled are adjustedand prepared in advance, and one set of the rolls having a suitablewidth is selected and changed every time the size of the shape steel ischanged. The operation of changing the roll is very time-consuming andincreases the production cost.

Recently, to improve the changing operation of the roll, a rolling millstructure wherein the barrel width of a horizontal roll for rolling ashape steel is variable has been put into practice. For example, inrolling of an H-shape steel, a universal mill or an edger mill capableof corresponding to a change of product specification is adopted, or arolling-mill roll of which a barrel width is adjustable in accordancewith the change of the specification is mounted.

For example, Japanese Unexamined Patent Publication No. 62-156007discloses a rolling-mill roll of a barrel-width adjustable type having aroll section fixed at a position in the axiswise direction and coupledto a drive side, and another roll section movable in the axiswisedirection by means of a barrel width adjustable screw. A barrel widthcorresponding to the width of a rolled shape steel can be set bychanging the relative axiswise position of both the roll sections bymeans of the barrel width adjustment screw.

Such a rolling-mill roll of a barrel-width adjustable type requires amechanism for transmitting torque from the drive side roll section tothe roll for operating the width adjustment. According to one example ofsuch transmission mechanism, a rod portion coaxially projected from thedrive side roll section is inserted into the other roll section andfixedly coupled thereto by a spline or key.

DISCLOSURE OF THE INVENTION

According to the above-mentioned roll of a barrel-width adjustable type,the spline or key for coupling the roll sections is located at aposition within a rolling width which coincides with the flange width ofthe H shape steel, and this position is at the side further frombearings of the movable roll section and nearer the rolling region.

Generally speaking, a large bending moment is generated in the rollduring the rolling operation due to the rolling reaction, which momentis largest at a center of the rolling width and becomes smaller closerto the axiswise end portion of the roll. Accordingly, in the structurewherein the spline or key is built-in in the rolling region, a stressconcentration is liable to occur due to not only the irregular profilethereof but also to the bending load caused by the rolling reaction.

Since there is a problem of stress concentration in the portion of thekey or spline in the conventional roll, as described above, it isnecessary, for example, to limit the rolling load to below a certainvalue or to strengthen rolls and other parts with high quality andexpensive materials. In this regard, while it is also possible toincreasing a roll size to improve the roll strength, this results in theenlargement of a total size of the installation, which is then far fromthe optimum design.

The present invention provides a rolling-mill roll of a barrel-widthadjustable type being more compact in size and free from stressconcentration.

Specifically, the barrel-width adjustable type rolling-mill roll isadapted to have an improved mechanical strength by preventing stressconcentration from occurring in a coupling structure between a driveside roll and the other side roll. The gist thereof is as follows:

(1) A rolling-mill roll of a barrel-width adjustable type comprising anarbor provided on a roll drive side, a connecting rod coaxiallyprojected from the arbor, and a sleeve into which the connecting rod isinserted to be movable in the axiswise direction, all of which aresupported in a bearing box via bearings, wherein two roll sections aremounted onto the outer circumferences of the arbor and the sleeve,respectively, to form two divided roll sections so that a distancebetween both the roll sections is adjustable by varying the relativeaxiswise positions of the sleeve and the arbor, characterized in that atorque transmission structure for transmitting the torque from theconnecting rod to the sleeve is based on the complementary engagementbetween the outer circumference of the connecting rod and the innercircumference of the sleeve, and the axiswise position of the engagementis located closer to an end portion of the roll than to the center ofthe bearing for supporting the outer circumference of the sleeve so thata stress concentration is prevented from occurring during the rollingoperation.

(2) A rolling-mill roll of a barrel-width adjustable type according to(1), wherein a barrel-width adjustment screw shaft is provided at an endportion of the connecting rod and a clutch mechanism is provided, at oneend of the screw shaft, which comprises a clutch shift cylinder, a slidebox which is not spatially rotatable and has a gear part in the interiorthereof, and a sleeve engagement gear synchronously rotatable with thesleeve.

(3) A rolling-mill roll of a barrel-width adjustable type forming twodivided roll sections comprising two divided sleeve sections in thewidthwise direction and inserted into an arbor as a common roll shaft tocause the sleeve sections to be movable thereon in the axiswisedirection, all of which are mounted in a bearing box via bearings,wherein two roll sections are mounted onto the outer circumferences ofthe sleeve sections, respectively, so that a distance between the rollsections is adjustable by varying the relative axiswise positions of thesleeve sections and the arbor, characterized in that a torquetransmission structure for transmitting the torque from the arbor to thesleeve is based on the complementary engagement between the outercircumference of the arbor and the inner circumference of the sleeve,and the axiswise position of the engagement is located closer to an endportion of the roll than to a center of the bearing for supporting theouter circumference of the sleeve so that a stress concentration isprevented from occurring during the rolling operation.

(4) A rolling-mill roll of a barrel-width adjustable type according to(3), wherein a barrel-width adjustment screw shaft is provided at an endportion of the arbor and a clutch mechanism is provided, at one end ofthe screw shaft, which comprises a clutch shift cylinder, a slide boxwhich is not spatially rotatable and has a gear part in the interiorthereof, and a sleeve engagement gear synchronously rotatable with thesleeve.

(5) A rolling-mill roll of a barrel-width adjustable type according to(1) or (3), wherein the torque transmission means is based on a splineor key engagement.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic side sectional view of a barrel widthadjustable type rolling-mill roll according to the present invention.

FIG. 2 shows an example of a maim part according to the presentinvention when a screw shaft is engaged with a slide engagement gear.

FIG. 3 is a cross-sectional view of one example of a spline structurebetween a connecting rod and a sleeve.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention provides a horizontal roll used for rolling shapesteels, which is capable of varying a rolling width to enable therolling of shape steels having various sizes, without the necessity ofreplacement of the roll, and is also improved in the structural strengthbecause the stress concentration inherent to the conventional dividedroll is prevented in a coupling zone between the two roll sections. Thatis, according to the present invention, the strength of the arboragainst rolling torque, bending or torsion is improved compared with theprior art, because no notch effect occurs in the coupling zone, and thusa divided type roll structure of a compact size is attained.

According to a first aspect of the present invention, to prevent stressfrom concentrating in a torque transmission structure for transmittingthe torque from a drive side roll section to another roll section, aconnecting rod coaxially projected from an arbor on the drive side isinserted into a sleeve, and the roll sections mounted onto the arbor andthe sleeve, respectively, are supported in a housing via bearings,wherein the connecting rod is coupled to the sleeve via a screw shaft sothat the sleeve is movable in the axial direction to provide arolling-mill roll capable of varying the barrel width. Further, a torquetransmission structure of the rolling-mill roll based on thecomplementary engagement between the arbor and the sleeve by means of aspline, a key or others is located at a position offset toward an outerend from the axial center of the sleeve bearing so that the engagementis not affected by a stress concentration and bending due to the rollingreaction.

According to a third aspect of the present invention, an arbor common totwo sleeve sections is inserted thereinto, and roll sections are mountedto the respective sleeve sections supported in a housing by bearings,wherein the arbor and the sleeve section are coupled with each other viaa screw shaft so that the sleeve section is movable in the axialdirection to result in the variation of the barrel width. The torquetransmission structure for the rolling-mill roll is the same as that ofthe first aspect.

According to the above structures, the rolling reaction during therolling operation is transmitted from the roll to the arbor and sleeve,and the maximum bending stress is applied to the sleeve area on whichthe roll is mounted and the arbor side connecting rod. Since noirregular profile for the purpose of the complementary engagement existsin this area of the sleeve and the connecting rod, a stressconcentration therein is prevented. In addition, since the position ofthe complementary engagement is offset from a center of the bearingtoward the roll outer end, a heavy load caused by the bending is allborne by the bearing so that the load applied on the engagement part ismitigated to a great extent even to zero, while only a small loadnecessary for the torque transmission is applied thereto.

The present invention will be described below in more detail withreference to the preferred embodiments illustrated in the drawings.

FIG. 1 is a sectional view of an embodiment of a rolling-mill roll of abarrel-width adjustable type as seen along a path of a shape steel to berolled. Reference numeral 11 denotes an H shape steel to be clutch shiftcylinder 7a and an internal gear part, and a sleeve engagement gear 7crotatable in synchronism with the sleeve 4.

The clutch mechanism 7 is capable of selectively rotating the screwshaft 9 in synchronism with the sleeve 4 and the arbor 2 rotatingtherewith, or stopping the spatial rotation thereof.

That is, if a rod of the clutch shift cylinder 7a projects outward, thegear part of the slide box 7b is meshed with the gear part of the screwshaft 9 as shown in FIG. 1 to maintain the screw shaft 9 not to bespatially rotatable. If the arbor 2 and the sleeve 4 are made to rotateby a mill motor (not shown) in this state, the screw shaft 9 movesrightward or leftward relative to the arbor 2 via the screw engagementbetween the female thread 4a and the screw shaft 9, whereby the axialrelative position of the arbor 2 to the sleeve 4 can be changed toadjust a distance between the roll sections 3a, 3b.

Thereafter, a path line is corrected by axially moving the arbortogether with the sleeve by the path line centering motor 6c.

On the other hand, if the rod of the clutch shift cylinder 7a isretreated, the sleeve engagement gear 7c is meshed with the screw shaft9 as shown in FIG. 2. Accordingly, the screw shaft 9 is rotated insynchronism with the sleeve 4 while keeping the same engagement statebetween the female screw 4a and the screw shaft 9, whereby the axialrelative position of the arbor 2 to the sleeve 4 is unchanged tomaintain a constant distance between both the roll sections 3a, 3b.

For example, the correction is carried out in the following manner whenthe width of the upper horizontal roll has been widened by W. After therolling operation at the barrel width of B has been completed, thebarrel width is adjusted to B+W. Then, the roll section 3a is immobilebecause the axial movement thereof is inhibited rolled by an upperhorizontal roll consisting of horizontal roll sections 3a, 3b, a lowerhorizontal roll consisting of horizontal roll sections 5a, 5b, and apair of vertical rolls 12, 13. While the following explanation will bemade exclusively on the upper horizontal roll 3, this is also true tothe lower horizontal roll 5.

In this drawing, an arbor 2 coupled to a drive motor and a reductiongear mechanism (not shown) is supported by a bearing 1c in a drive sidebearing box 1a.

The arbor 2 has a connecting rod 2a coaxially projected therefrom andthe roll section 3a integrally carried on the outer circumferencethereof at a position closer to the bearing 1c.

The rod 2a is inserted into a sleeve 4 rotatably supported by a radialbearing Id accommodated in a driven side bearing box 1b. That is, thesleeve 4 is movable in the axial direction of the roll but inhibitedfrom the rotation relative to the arbor by a torque transmission means(spline 8 in this embodiment). A roll section 3b mated with the arborside roll section 3a is mounted on the outer circumference of the sleeve4 at a position closer to an inner end thereof. The sleeve 4 is coupledto the bearing box 1b via a bearing 6a and a screw ring 6b so that thearbor and the sleeve are integrally movable in the axial directioneither rightward or leftward by the action of a path line centeringmotor 6c for shifting the screw ring 6b. On the other hand, the bearingbox la is supported in the axial direction of the roll by a pressingdevice 10 attached to a housing (not shown).

A screw shaft 9 for adjusting a barrel width is provided while abuttingon the outer end of the connecting rod 2a, to be screw-engaged with afemale thread 4a of the sleeve 4. At a leftside end of the screw shaft 9is provided a clutch mechanism 7 including a slide box 7b which is notspatially rotatable and has a by the housing via the arbor 2 and thebearing box 1a, but the roll section 3b solely moves leftward in thedrawing by W. This means that a roll center is offset leftward by half aW from the path line center defined as an arrangement center of therolling line. Therefore, it is necessary to shift the horizontal roll asa whole, together with the arbor and the sleeve, in the axial directionby the path line centering motor 6c so that the roll center coincideswith the path line center.

The spline 8 provided at a base end of the connecting rod 2a fortransmitting the torque from the arbor 2 to the sleeve 4 may be of anykind usually used as a machine element; for example, ribs 8a and grooves8b provided on the outer circumference of the connecting rod 2a and theinner circumference of the sleeve 4, respectively, to be fitted witheach other as shown in FIG. 3 in an enlarged scale. The torquetransmission structure formed by the spline 8 is provided at a positionoffset outward from the axial center of the bearing Id as shown in FIG.1.

In the above structure, the rolling reaction during the rollingoperation is applied from the roll sections 3a, 3b to the arbor 2,sleeve 4 and connecting rod 2a. There is no irregular profile, such asspline or others, in the area between the roll sections 3a, 3b and thecenter line of the bearing 1d as in the prior art, but the surfacecontour of these members is smooth and flat. Accordingly, a stressconcentration hardly occurs in this area due to the rolling reaction,whereby the roll structure is sufficiently durable against the rollingreaction force, without increasing a diameter of such members or using ahigh quality material for the manufacture thereof.

Since the spline 8 on which the stress is liable to concentrate islocated at a position offset outward from the axial center of thebearing 1d, most of the load caused by the bending due to the rollingreaction is borne by the bearing 1d so that the spline 8 is not affectedthereby. Accordingly, the stress caused by the bending is prevented fromconcentration onto the spline 8, whereby the strength problem iseliminated.

In this regard, even when a key and a key-groove for transmitting therotation of the arbor 2 is used instead of providing the spline 8between the connecting rod 2a and the sleeve 4, the strength problem canbe solved by locating the key and key groove at a position correspondingto that of the above spline 8.

According to a third aspect of the present invention, an arbor common totwo roll sections is inserted into the two sleeve sections on which theroll sections are mounted, respectively, so that a symmetric arrangementis obtained. In this case, the torque transmission means is located at aposition offset outward from the axial center of the bearing, similar tothe first aspect, so that the same effect is obtainable as the firstaspect.

Table 1 shows the comparison between the first aspect of the presentinvention applied to an actual roll mill and the prior art. It isapparent from this Table that the rolling-mill roll according to thepresent invention is durable against a force caused by the rollingreaction approximately 1.5 times to 2.3 times that durable by theconventional one if both the rolling-mill rolls have the same rolldiameter and are made of the same material. Also, since the adjustmentrange of barrel width is approximately 1.7 times that of theconventional one, the roll design is significantly enhanced.

                  TABLE 1                                                         ______________________________________                                                     Present Invention                                                                        Prior Art                                             Profile        R:100    R:10    R:100  R:10                                   ______________________________________                                        Arbor  Bending Stress                                                                            63.1     43.0  100    100                                  strength                                                                             Result. Stress                                                                            63.0     42.9  100    100                                  ______________________________________                                    

wherein a profile of prior art torque transmission means: 545 mm×505 mmφ

the adjustment range of prior art reduction roll: 75 mm

a profile of inventive torque transmission means: 545 mmφ

the adjustment range of inventive reduction roll: 130 mm

INDUSTRIAL APPLICABILITY

According to the present invention, since a drive side arbor is coupledto a sleeve for the torque transmission by the complementary engagementbetween the profiled members such as spline or key located at a positionapart from a point at which the bending due to the rolling reactionmainly occurs, it is possible to simplify the configuration of arbor andsleeve portions in which bending occurs, so that the stressconcentration is prevented. Therefore, it is possible to obtain a properstrength of the rolling-mill roll without increasing the outer diameterof the arbor or sleeve, and also to provide a larger rolling load.

If the position of the spline or key is offset outward from the axialcenter of the bearing for supporting the sleeve on the housing, a forcecaused by the bending is borne by the bearing and the stressconcentration due to the provision of the spline or key is mitigated.

We claim:
 1. A rolling-mill roll of a barrel-width adjustable typecomprising an arbor provided on a roll drive side, a connecting rodcoaxially projected from the arbor, and a sleeve into which theconnecting rod is inserted to be movable in the axiswise direction, allof which are supported in a bearing box via bearings, wherein two rollsections are mounted onto the outer circumferences of the arbor and thesleeve, respectively, to form two divided roll sections so that adistance between both the roll sections is adjustable by varying therelative axiswise positions of the sleeve and the arbor, characterizedin that a torque transmission structure for transmitting the torque fromthe connecting rod to the sleeve is based on the complementaryengagement between the outer circumference of the connecting rod and theinner circumference of the sleeve, and the axiswise position ofengagement is located closer to an end portion of the roll than to acenter of the bearing for supporting the outer circumference of thesleeve, so that a stress concentration is prevented from occuring duringthe rolling operation.
 2. A rolling-mill roll of a barrel-widthadjustable type according to claim 1, wherein a barrel width adjustmentscrew shaft is provided at an outer end of the connecting rod, and aclutch mechanism is provided at one end of the screw shaft, whichcomprises a clutch shift cylinder, a slide box which is not spatiallyrotatable and has a gear part in the interior thereof, and a sleeveengagement gear synchronously rotatable with the sleeve.
 3. Arolling-mill roll of a barrel-width adjustable type according to claim1, wherein the torque transmission means is based on a spline or keyengagement.
 4. A rolling-mill roll of a barrel-width adjustable typeforming two divided roll sections comprising two divided sleeve sectionsin the widthwise direction and inserted into an arbor as a common rollshaft to cause the sleeve sections to be movable thereon in the axiswisedirection, all of which are mounted in a bearing box via bearings,wherein two roll sections are mounted onto the outer circumferences ofthe sleeve sections, respectively, so that a distance between the rollsections is adjustable by varying the relative axiswise positions of thesleeve sections and the arbor, characterized in that a torquetransmission structure for transmitting the torque from the arbor to thesleeve is based on the complementary engagement between the outercircumference of the arbor and the inner circumference of the sleeve,and the axiswise position of the engagement is located closer to an endportion of the roll than to a center of the bearing for supporting theouter circumference of the sleeve so that a stress concentration isprevented from occurring during the rolling operation.
 5. A rolling-millroll of a barrel-width adjustable type according to claim 4, wherein abarrel width adjustment screw shaft is provided at an end portion of thearbor and a clutch mechanism is provided at one end of the screw shaft,which comprises a clutch shift cylinder, a slide box which is notspatially rotatable and has a gear part in the interior thereof, and asleeve engagement gear synchronously rotatable with the sleeve.
 6. Arolling-mill roll of a barrel-width adjustable type according to claim3, wherein the torque transmission means is based on a spline or keyengagement.